F number and aperture?


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schizer

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Feb 6, 2008
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#1
hey guys, i'm wondering whats the relation between the two? i'm a noob, so i have hardly any idea about their relationships.. it seems like the numbers are kinda close, and some threads which i've read said something about the max and min of the F number limits the the size of the aperture.. is that true?

i'm thinking of getting the sony h-7, and its F number is 2.7-4.5, with aperture of 2.7-8.. so does this mean the limit of aperture is til 4.5 instead of 8?
 

flipfreak

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Nov 26, 2007
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#2
they pretty much refer to the same thing. for the h7, the first set of numbers represent the widest aperture in the widest end of the lens and the tele end of the lens. the 8 refers to the smallest aperture on the tele end.
 

jfoo

Senior Member
Apr 7, 2004
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#3
when you shoot wide angle, the largest aperture you can select is 2.7.

when you shoot telephoto, the largest aperture you can select is 4.5.
 

lsisaxon

Senior Member
Nov 29, 2004
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#4
hey guys, i'm wondering whats the relation between the two? i'm a noob, so i have hardly any idea about their relationships.. it seems like the numbers are kinda close, and some threads which i've read said something about the max and min of the F number limits the the size of the aperture.. is that true?

i'm thinking of getting the sony h-7, and its F number is 2.7-4.5, with aperture of 2.7-8.. so does this mean the limit of aperture is til 4.5 instead of 8?
The largest aperture is f/2.7 at the wide end and the largest aperture at the tele end is f/4.5. The smallest aperture which the camera can stop down to is f/8 (same for most PnS with small sensors because of diffraction limits due to the small pixel dimension).
 

compro_1975

Senior Member
Apr 24, 2005
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#5
meanin to say the range is 2.7-8 f/stop

if i were to use it wo shoot wide picture, then i can use frm 2.7-8f/stop

but if i push the zoom to max, i will b oly able to shoot from 4.5-8f/stop right?
 

lsisaxon

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Nov 29, 2004
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#6
meanin to say the range is 2.7-8 f/stop

if i were to use it wo shoot wide picture, then i can use frm 2.7-8f/stop

but if i push the zoom to max, i will b oly able to shoot from 4.5-8f/stop right?
Yes... :) The correct way to write is f/2.7-f/8 and f/4.5-f/8.
 

tunster

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Oct 26, 2003
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#7
Aperture refers to the physical object (the almost circular part) of your camera. F-stop is the unit to measure it.

Meaning.... just like a Ruler and CM...what's the relation? Ruler is an object. CM is the unit.
 

compro_1975

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Apr 24, 2005
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#8
lsisaxon tks to all the reply you had given me, i would want to draw your attention to this: http://www.tamron.com/assets/vs2/pdfs/a20.pdf the last page, i see the similar situation, it stated max aperture F/3.5-6.3 below it, it states Minimum Aperture [FONT=EBUYIY+AkzidenzGroteskBE-Regul,Akzidenz Grotesk]F/22~F/40 (28mm~300mm), it is of the same prinple that at 28, i my fastest lens is 3.5 and at 300, my fastest is 6.3?[/FONT]
 

tunster

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Oct 26, 2003
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#9
lsisaxon tks to all the reply you had given me, i would want to draw your attention to this: http://www.tamron.com/assets/vs2/pdfs/a20.pdf the last page, i see the similar situation, it stated max aperture F/3.5-6.3 below it, it states Minimum Aperture [FONT=EBUYIY+AkzidenzGroteskBE-Regul,Akzidenz Grotesk]F/22~F/40 (28mm~300mm), it is of the same prinple that at 28, i my fastest lens is 3.5 and at 300, my fastest is 6.3?[/FONT]
right
 

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